EP0873812A1 - Bearbeitungsmaschine mit laserstrahl sowie laser - Google Patents

Bearbeitungsmaschine mit laserstrahl sowie laser Download PDF

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Publication number
EP0873812A1
EP0873812A1 EP96928726A EP96928726A EP0873812A1 EP 0873812 A1 EP0873812 A1 EP 0873812A1 EP 96928726 A EP96928726 A EP 96928726A EP 96928726 A EP96928726 A EP 96928726A EP 0873812 A1 EP0873812 A1 EP 0873812A1
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EP
European Patent Office
Prior art keywords
laser
oscillation
burst
signal
continuous
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EP96928726A
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English (en)
French (fr)
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EP0873812A4 (de
Inventor
Osamu Kenkyusho of Komatsu Ltd. WAKABAYASHI
Tetsuo Kenkyusho of Komatsu Ltd. SHAKUSHI
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Komatsu Ltd
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Komatsu Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/062—Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/13—Stabilisation of laser output parameters, e.g. frequency or amplitude
    • H01S3/131—Stabilisation of laser output parameters, e.g. frequency or amplitude by controlling the active medium, e.g. by controlling the processes or apparatus for excitation
    • H01S3/134—Stabilisation of laser output parameters, e.g. frequency or amplitude by controlling the active medium, e.g. by controlling the processes or apparatus for excitation in gas lasers

Definitions

  • the present invention relates to a laser processing device comprising a laser device which performs a burst operation, and a processing device which subjects a semiconductor, macromolecular material, or inorganic material to a predetermined type of work using the laser light produced from the laser device.
  • steppers In reduction projection exposure devices (referred to as "steppers" hereinbelow) which use a laser to carry out the exposure processing of a circuit pattern, the amount of exposure needs to be strictly controlled in order to maintain the resolution of the circuit pattern above a certain level.
  • the excimer lasers used as light sources for such steppers are what are known as pulse-discharge excitation gas lasers, the pulse energy of every pulse varies, and there is a need to reduce this variation in order to improve the precision with which the amount of exposure is controlled.
  • the mode of operation of the excimer laser constituting the light source is inevitably a burst mode involving the repetition of an operation in which laser light is continuously oscillated in pulses a predetermined number of times, and then the pulse oscillation is stopped for a predetermined time.
  • the burst mode involves the alternate repetition of a continuous pulse oscillation time and an oscillation-stopping time.
  • continuous pulse and “continuous pulse oscillation” are referred to in this specification, they are used with the meaning that pulse discharge is repeatedly carried out and successive pulse laser light can be repeated; and they are used with a different meaning from “continuous oscillation laser” and “CW oscillation” as referred to more generally.
  • excimer lasers are pulse discharge excitation gas lasers
  • Reasons for this include that the discharge produces density disturbances in the laser gas within the discharge space and causes the subsequent discharge to become non-uniform and unstable, and that such non-uniform discharges and the like produce local temperature increases at the surfaces of the discharge electrodes, and cause degradation of the subsequent discharge and cause the discharge to become non-uniform and unstable.
  • this tendency is marked at the start of the abovementioned continuous pulse oscillation period, and a phenomenon known as spiking occurs whereby, as shown by the portion S in Figure 8 (a), relatively high pulse energy is obtained in the initial pulses following the passage of an oscillation-stopping period, but then the discharge degrades and the pulse energy gradually reduces.
  • a phenomenon known as spiking occurs whereby, as shown by the portion S in Figure 8 (a), relatively high pulse energy is obtained in the initial pulses following the passage of an oscillation-stopping period, but then the discharge degrades and the pulse energy gradually reduces.
  • Ps constant pulse energy
  • excimer laser devices operating in burst mode have problems in that the abovementioned variation in the energy of each pulse reduces the precision with which the amount of exposure is controlled, and the phenomenon of spiking also markedly increase such variation and greatly reduces the precision with which the amount of exposure is controlled.
  • step & scan methods in which exposure is carried out while moving the mount.
  • step & scan methods because the exposure is carried out while moving the mount, it is not possible to use the conventional technique whereby variations in the total amount of exposure are reduced by increasing the number of exposure pulses as discussed above, and other techniques have to be used to ensure control such that the pulse energy of each pulse is uniform.
  • the laser side is arranged so as to receive the laser oscillation synchronization signal TR for carrying out continuous pulse oscillation sent from the stepper side, and to carry out continuous pulse oscillation synchronously with the laser oscillation synchronisation signal TR which are received; only passive control being carried out on the laser side.
  • the stepper side desires the laser oscillation to be in. This is to say, information such as the cycle of the continuous pulse oscillation, the number of continuous pulse oscillations, whether the oscillation-stopping mode is currently in effect or not, and the oscillation-stopping time is all unknown information, but the laser side has to be arranged so as to be always able to effect the correct discharge voltage control without prior warning whenever a laser oscillation synchronization signal is input.
  • charge voltage data for matching the energy of each pulse of the continuous pulse oscillation with a predetermined target value Ps, is prestored in memory, for each pulse of the continuous pulse oscillation (what number pulse it is), using the oscillation-stopping time, the charge voltage value and the like as parameters. Further, whenever continuous pulse oscillation is carried out, the pulse energy of each pulse at that time is stored in memory, and the stored items of data are used for charge voltage control of each pulse during the subsequent continuous pulse oscillation.
  • each of the preceding pulse energy values which have been stored in memory is compared with the target value Ps, the abovementioned charge voltage data of each pulse, which has been stored in memory, is corrected in accordance with the results of the comparison, and charge voltage control is performed in accordance with the corrected charge voltage data.
  • the laser side incorporates a timer which carries out a timing action by counting a system clock signal of a cycle shorter than the cycle of the laser oscillation synchronization signal TR, and is arranged so as to make a judgment as to whether the current system clock input instant is during the continuous oscillation or during the oscillation-stopping time, by comparing the timing output of this timer with a predetermined set time, and is arranged in such a way that, using the result of this judgment, it computes the optimum charge voltage value for each system clock input instant by carrying out the correction computation for the charge voltage discussed above at this instant, and controls the charge capacitor so as to achieve the computed charge voltage at each system clock input instant.
  • the charge voltage data corresponding to this assumed oscillation-stopping time Tpp is read out, a computation is carried out whereby the charge voltage data is corrected using the results of a comparison between the target value Ps for the pulse energy value and the monitor value of the first burst of energy of the preceding continuous pulse oscillation, and the charge capacitor is controlled so as to achieve the computed charge voltage.
  • the power source circuit for the discharge is always in standby mode always so as to always obtain the optimum charge value for that moment, regardless of the fact that it may be during the oscillation-stopping time, in such a way that a laser oscillation synchronization signal TR may be input at any time.
  • various control tasks are carried out including, on the laser device side, charge voltage control as discussed above in which the target pulse energy Ps is received from the exposure device, in such a way as to achieve the received target pulse energy Ps.
  • charge voltage control is carried out by monitoring the energy of each laser pulse actually output, and comparing the target pulse energy Ps and the monitored value, as discussed above.
  • the monitored value on the laser device side is no more than the monitored value of the energy on the laser device side, and this does not necessarily coincide with the laser energy value in the stage when the exposure is actually performed. This is to say, it sometimes happens that the monitored value of the energy on the laser device side fails to coincide with the laser energy value in the stage when the exposure is actually performed for reasons such as drift of the energy monitor of the laser device, and changes in the transmittance in the exposure device caused by mode changes in the laser beam (for example, for reasons such as part of the laser beam being kicked by a slit or the like provided in the laser-incidence aperture of the exposure device caused by widening of the laser beam).
  • the monitored value differs from the laser energy value in the stage when the exposure is actually performed, and accurate exposure control cannot therefore be carried out, since the output of a monitor placed on the laser device side is used for the monitored energy value of the laser pulse.
  • This invention has taken this situation into account and aims to provide a laser processing device which provides for stability in the laser device without requiring charge control during laser oscillation stopping operation, and which is able to perform high-precision laser output constancy control, and is able to improve the responsiveness and control speed of various other control tasks.
  • This invention further aims to provide a laser processing device which is able to perform accurate exposure control by correcting for variations in the transmittance of the laser output, and variations in the laser output monitor.
  • This invention provides a laser processing device comprising: a laser device for carrying out a burst mode operation involving alternate repetition of a continuous oscillation operation wherein laser light is continuously subjected to pulse oscillation in a predetermined cycle for a predetermined number of times and a stopping operation wherein the continuous pulse oscillation is stopped for a predetermined time after the continuous oscillation operation; and a processing device for performing a predetermined type of work by means of the laser light produced by the laser device, characterized in that: the processing device comprises burst-on/off signal transmitting means which produces a burst-on signal for starting the continuous oscillation operation and a burst-off signal for stopping the continuous oscillation operation and starting the stopping operation, and transmits the burst-on and -off signals to the laser device; and the laser device comprises control means which receives the burst-on signal and the burst-off signal and performs control relating to the burst operation using these signals.
  • pulse oscillation in the abovementioned laser device may be carried out synchronously with a laser oscillation synchronization signal transmitted from the processing device to the laser device, or may be carried out synchronously with a laser oscillation synchronization signal produced by the laser device itself.
  • the laser device performs control relating to the burst operation using a burst-on signal and burst-off signal sent from the processing device side.
  • the arrangement is such that the laser oscillation synchronization signal is produced by the laser device itself
  • the arrangement is such that the laser oscillation synchronisation signal is produced after receipt of the burst-on signal, and a burst-off signal is transmitted after the laser oscillation synchronisation signal, then, on the laser device side, it is sufficient to carry out charge voltage control for spiking-prevention control from the instant when the burst-on signal is input until the instant when the first laser oscillation synchronization signal is input, and there is no need to carry out charge voltage control during the time when the laser oscillation is stopped.
  • this invention provides a laser processing device comprising: a laser device which carries out a burst mode operation involving alternate repetition of a continuous oscillation operation wherein laser light is continuously subjected to pulse oscillation for a predetermined number of times and a stopping operation wherein the continuous pulse oscillation is stopped for a predetermined time after the continuous oscillation operation; and a processing device which performs a predetermined type of work by means of the laser light produced by the laser device, characterized in that:
  • the target energy value of the continuous pulse oscillation which has been set in advance, is corrected using the result of a comparison of the laser monitor output on the processing device side and the laser monitor output on the laser device side, and exposure constancy control is performed using this corrected target energy value as the target value.
  • Figure 1 shows a first embodiment of a case in which a bandwidth-narrowing excimer laser 1 is used as a laser device, and a stepper 20 which carries out reduction projection exposure processing of the circuit pattern of a semiconductor is used as a processing device.
  • the laser chamber 2 of the excimer laser 1 has discharge electrodes and the like which are not depicted, and laser oscillation is carried out by using a discharge between the discharge electrodes to stimulate a laser gas comprising Kr, F2, Ne or the like filling the inside of the laser chamber 2.
  • the light which is produced is returned back to the laser chamber 2 where it is amplified, is converted to a narrow bandwidth by a bandwidth-narrowing unit 3, and is output as oscillation laser light L via a front mirror 4.
  • some of the light returns back from the front mirror 4 to the laser chamber 2, where laser oscillation occurs.
  • the laser light L is output successively by means of a burst mode operation involving alternate repetition of a continuous oscillation operation involving oscillation of pulses continuously in a predetermined cycle and for a predetermined number of times, and a stopping operation in which the abovementioned continuous pulse oscillation is stopped for a predetermined time after the continuous oscillation operation.
  • the laser power source circuit 5 carries out the discharge by applying a potential difference V across the abovementioned discharge electrodes in accordance with voltage data supplied from a laser controller 6. It should be noted that, in the laser power source circuit 5, the discharge is carried out by the action of a switch element, such as a thyratron or the like, once the discharge voltage has been charged by a charge circuit which is not depicted.
  • a switch element such as a thyratron or the like
  • the energy E of each pulse of the output laser light L is detected.
  • the detected energy value E is input to the laser controller 6.
  • items of data such as the spectral line width and wavelength of the laser light L are detected by means of a spectroscope and line sensor, which have been omitted from the depiction, and these items of data are also input into the laser controller 6.
  • the following signals are input into the laser controller 6 from the exposure device 20:
  • control operations associated with the present invention based on these input signals, the following control operations are mainly performed in the laser controller 6.
  • the exposure device 20 is provided with a beam splitter 11 which samples some of the laser light L which falls incident upon it via a slit 10, and the sampled light falls incident upon a monitor module 12.
  • the energy Pi' of each pulse of the incident laser light L is detected by the monitor module 12, and the detected energy values Pi' are input to an exposure device controller 13. It should be noted that the laser light which passes through the beam splitter 11 is used in the reduction exposure process.
  • the following processes associated with the present invention are performed in addition to controlling the movement of a mount on which a wafer is mounted and the reduction exposure process.
  • the mode of the burst signal BS is always assessed, and various different processing tasks are performed in accordance with the results of the assessment (Step 100).
  • the corrected target pulse energy Pd is sent from the exposure device 20 during the burst-stopping period when the burst signal BS is in the off mode, and therefore this target pulse energy Pd is received and stored in memory (Step 110). Further, the laser controller 6 performs other processes (Step 120) apart from the charge voltage control during this burst-stopping period.
  • the laser controller 6 performs a process as outlined below during the period (time t1 in Figure 2) from the instant of this rise until the first laser oscillation synchronization signal TR is input.
  • the laser controller 6 incorporates a timer which times the oscillation-stopping time te (see Figure 2) from the instant when the burst signal BS turns off until it turns on, and, when the burst signal BS rises to on, the laser controller 6 takes in the output te of this timer, and takes in the corrected target pulse energy Pd sent from the exposure device 20 during the immediately preceding burst-stopping time (Step 200).
  • the laser controller 6 computes (Step 210) the true oscillation-stopping time Tpp at the instant when the first laser oscillation synchronization signal TR is input, in accordance with the following equation.
  • Equation (2) is more accurate since the true oscillation-stopping time Tpp is the period from when the last laser oscillation synchronization signal TR of the former burst cycle is produced until the initial laser oscillation synchronization signal of the current burst cycle, TR is produced.
  • the laser controller 6 calculates (Step 220) the charge voltage V1 for the current first laser oscillation using the abovementioned target pulse energy Pd which was taken in, and the oscillation-stopping time Tpp.
  • the optimum charge voltage values for obtaining a constant pulse energy are stored in memory in advance as a voltage data table, for each oscillation sequence number i, using various values of the target pulse energy Pd and the oscillation-stopping time Tpp as parameters.
  • Figure 4 shows the results of tests under a total of six different conditions when, in the initial burst oscillation period, the target pulse energy Pd was varied between three different values P1, P2 and P3 (P1 ⁇ P2 ⁇ P3), and the oscillation-stopping time Tpp was varied between two different values ta and tb (ta ⁇ tb):
  • Figure 4 (a) showing the pulse energy monitored values for each oscillation sequence number i
  • Figure 4 (b) showing the charge voltage values Vi for each oscillation sequence number i.
  • charge voltage data as shown in Figure 4 for constancy control of the pulse energies during continuous pulse operation to a predetermined target value, is stored in advance in memory, for each oscillation sequence number i, using the target pulse energy Pd and oscillation-stopping time Tpp as parameters.
  • the various pulse energy monitored values are input from the monitor module 8 to the laser controller 6, and these monitored values are given a correspondence with the oscillation sequence numbers i and stored in memory by the laser controller 6.
  • the laser controller 6 When the charge voltage of the first pulse is calculated, the laser controller 6 first reads out, from the abovementioned voltage data table, the charge voltage value corresponding to the first pulse and corresponding to the target pulse energy Pd and oscillation-stopping time Tpp taken in in the processing of Step 200. Then, the abovementioned monitored value of the energy of the first pulse of the preceding continuous pulse oscillation, which was stored in memory, is compared with the target pulse energy value Pd input from the abovementioned exposure device 20, the charge voltage value read out from the abovementioned voltage data table is corrected in accordance with the result of this comparison, and the result of this correction is output (Step 230) to the power source circuit 5 as the current, which is to say the first pulse oscillation charge voltage value V1.
  • a technique for the abovementioned correction computation there is, for example, a technique in which the difference between the monitored value of the energy of the preceding first pulse and the target pulse energy value Pd is determined, and correction is not carried out when this difference is less than a predetermined set value, while the charge voltage value is increased or decreased in accordance with the positive or negative attribute ( ⁇ ) of the abovementioned difference when the difference is more than a set value.
  • the laser controller 6 stores in memory the pulse energy P monitored by the monitor module 8, and the charge voltage value V1. This stored data is used in the calculation of the first charge voltage of the subsequent continuous pulse oscillation.
  • oscillation conditions which are stored in memory include the target pulse energy Pd, oscillation-stopping time Tpp, and the pulse oscillation sequence numbers i.
  • the first pulse oscillation is carried out as outlined above.
  • Step 300 a computation which is basically the same as that for the first pulse oscillation is carried out (Step 300) during continuous pulse oscillation with the burst signal BS in the on mode.
  • the laser controller 6 stores in memory various oscillation conditions from the current pulse oscillation, the pulse energy P monitored by the monitor module 8, and the charge voltage value Vi. This stored data is used in the calculation of the i-th charge voltage of the subsequent continuous pulse oscillation.
  • the i-th pulse oscillation is carried out as outlined above.
  • the laser controller 6 calculates the cumulative energy Qe during a single burst period by integrating the pulse energy Pi monitored by the monitor module 8 during the current burst operation, and transmits (Step 400) the cumulative energy value Qe to the exposure device 20.
  • This cumulative energy value Qe is used in the correction computation of the target pulse energy Ps in the exposure device 20, as discussed above.
  • the arrangement was such that the stepper 20 produced both the burst signal BS and the laser oscillation synchronisation signal TR, and output this to the excimer laser 1, but in this second embodiment the arrangement is such that the laser oscillation synchronization signal TR is produced on the excimer laser 1 side, and laser pulse oscillation synchronized with the laser oscillation synchronisation signal TR is carried out by outputting, to the power source circuit 5, this laser oscillation synchronization signal TR produced by itself.
  • a signal such as is shown in Figure 2 above is sent from the stepper 20 side to the excimer laser 1, as in the first embodiment above.
  • the exposure device controller 13 of Figure 5 only the burst signal BS and target pulse energy Pd are output to the laser controller 6. Further, in the laser controller 6 of Figure 5, when the burst signal BS input from the exposure device controller 13 rises, as shown in Figure 2 above, the first laser oscillation synchronization signal TR is output after the passage of a time t1 from the instant of this rise, and Np laser oscillation synchronisation signals TR are output with a predetermined cycle ⁇ tp thereafter.
  • the mode of the burst signal BS is assessed, and various different processing tasks are performed in accordance with the results of the assessment (Step 100), as was the case previously.
  • the corrected target pulse energy Pd is sent from the exposure device 20 during the burst-stopping period when the burst signal BS is in the off mode, and therefore this target pulse energy Pd is received and stored in memory (Step 110). Further, the laser controller 6 performs other processes (Step 120) apart from the charge voltage control during this burst-stopping period. These processes are also as in the embodiment above.
  • the laser controller 6 computes (Step 201) the true oscillation-stopping time Tpp in accordance with the above Equation (1) or Equation (2), as in the embodiment above, during the period (time t1 in Figure 2) from the instant of this rise until the first laser oscillation synchronization signal TR is produced by itself, and calculates (Step 220) the charge voltage V1 for the current first laser oscillation, in the same way as above, using this computed oscillation-stopping time Tpp and the abovementioned target pulse energy Pd which has been taken in.
  • the laser controller 6 upon the passage of the abovementioned time t1 from the instant when the burst signal BS rose, the first laser oscillation synchronization signal TR is produced, and this is supplied to the power source circuit 5. As a result, discharge control based on a previously supplied charge voltage is performed by the power source circuit 5 (Steps 231 and 250).
  • the laser controller 6 stores in memory (Step 260) various oscillation conditions from the current pulse oscillation, the pulse energy P monitored by the monitor module 8, and the charge voltage value V1.
  • the laser controller 6 counts the number of pulse oscillations in the burst cycle, and assesses whether the counted value coincides with Np or not. If it does coincide, the laser oscillation in the burst cycle is ended (Steps 261 and 262).
  • Step 300 a computation which is basically the same as that for the first pulse oscillation is carried out (Step 300) during continuous pulse oscillation with the burst signal BS in the on mode.
  • the time since the preceding laser oscillation synchronisation signal TR was produced is timed and, if the elapsed time coincides with the cycle ⁇ tp of the abovementioned pulse oscillation, a laser oscillation synchronization signal TR for the current pulse oscillation is produced and supplied to the power source circuit 5.
  • discharge control based on a previously supplied charge voltage is performed by the power source circuit 5 (Steps 302 and 250).
  • the laser controller 6 stores in memory various oscillation conditions from the current pulse oscillation, the pulse energy P monitored by the monitor module 8, and the charge voltage value Vi.
  • Pulse oscillation containing Np laser pulses is performed as outlined above.
  • the laser controller 6 calculates the cumulative energy Qe during a single burst period by integrating the pulse energy Pi monitored by the monitor module 8 during the current burst operation, and transmits (Step 400) the cumulative energy value Qe to the exposure device 20.
  • This cumulative energy value Qe is used in the correction computation of the target pulse energy Ps in the exposure device 20, as discussed above.
  • the arrangement was such that the burst signal BS retains the on state during the period of the burst cycle, and burst-on is represented by its rise, and burst-off is represented by its fall, but, as shown in Figure 7, in this third embodiment the exposure device controller 13 only outputs a one-shot burst-on signal BS', and a burst-off signal is not output.
  • the laser oscillation synchronization signal TR may be produced by the exposure device controller 13 as in the first embodiment above, or may be produced by the laser controller 6 as in the second embodiment above.
  • the laser oscillation synchronization signal TR are produced by the exposure device controller 13
  • at least the number Np of laser oscillation synchronization signal TR in one burst cycle must be known in advance on the laser controller 6 side
  • at least the production cycle ⁇ tp of the laser oscillation synchronization signal TR and the abovementioned number Np must be known in advance on the laser controller 6 side.
  • the first laser oscillation synchronization signal TR is produced after the passage of a time t1 from the instant when the burst-on signal BS' is produced, and the burst-on signal BS' for the next burst cycle is produced after the passage of a time t3 from the instant when the last laser oscillation synchronization signal TR in a single burst cycle is produced.
  • the laser controller 6 can count the laser oscillation synchronization signal TR sent from the exposure device controller 13 and so make a judgment that the instant when the count value coincides with Np is burst-off. Further, on the exposure device controller 13 side, an assessment can be made that the instant when a time t3 has passed from the instant when Np laser oscillation synchronisation signal TR has been sent is the timing at which the next burst-on signal BS' is sent.
  • the laser controller 6 can count the laser oscillation synchronization signal TR sent from the exposure device controller 13 and so make a judgment that the instant when the count value coincides with Np is burst-off.
  • the arrangement is such that the signal-send timing of the burst-on signal BS' is known or confirmed on the exposure device controller 13 side either by transmitting a continuous pulse oscillation end signal (sent with the same timing as the last laser oscillation synchronization signal TR) indicating that the Np-th continuous pulse oscillation has ended from the laser controller 6 to the exposure device controller 13, or by letting the exposure device controller 13 know in advance the cycle ⁇ tp of the laser oscillation synchronization signal TR produced on the laser controller 6 side.
  • a continuous pulse oscillation end signal sent with the same timing as the last laser oscillation synchronization signal TR
  • the exposure device controller 13 can judge that the instant when the time t3 has passed from the instant when the continuous pulse oscillation end signal was received is the timing at which the next burst-on signal BS' is sent.
  • the arrangement was such that the charge voltage data stored in a charge voltage data table was corrected based on the pulse energy monitored values of the continuous pulse oscillation of the preceding cycle, but, depending on the exposure precision, the arrangement may be such that charge voltage control is carried out using the stored data of the charge voltage data table directly, without carrying out this correction.
  • the arrangement was such that the charge voltage data stored in the charge voltage data table was corrected based on the pulse energy monitored values from the continuous pulse oscillation of the preceding cycle, but the arrangement may be such that data from an even earlier continuous pulse oscillation is used. Further, the arrangement may be such that the correction process is carried out based on data from two or more continuous pulse oscillations, and not data from a single continuous pulse oscillation.
  • the arrangement was such that the laser excitation strength or discharge voltage was varied by controlling the charge voltage, but the excitation strength or discharge voltage may be controlled using another technique.
  • the excitation strength or discharge voltage may be controlled using another technique.
  • the strength of the light of a flash lamp may be controlled.
  • a single IC chip on a wafer may be exposed during the period of one burst from burst-on to burst-off, but a plurality of IC chips may be exposed during this period of a single burst.
  • the laser device was arranged so as to measure the cumulative pulse energy and send this cumulative pulse energy to the exposure device, but it may also be arranged in such a way that the average pulse energy, obtained by dividing the cumulative pulse energy by the number of pulses within a single burst, is sent to the exposure device. Further, when a scan system is involved, the cumulative value of the moving cumulative pulse energy may be used. Further, parameter values other than pulse energy, for example the target wavelength or the like, may be sent.
  • the arrangement was such that the charge voltage value for the first pulse oscillation is computed in the period from when the abovementioned burst signal BS turns on until the first laser oscillation synchronization signal TR is received, and computations of the excitation strengths of pulse oscillations from the second onward are carried out in the periods from when a laser oscillation synchronization signal is received until the next laser oscillation synchronization signal is received, but the arrangement may also be such that the charge voltage values of all of the pulse oscillations of the current continuous pulse oscillation are calculated in the period from when the burst signal BS turns on until the first laser oscillation synchronization signal TR is received.
  • the exposure device 20 did not send a charge signal to the excimer laser 1, but it may send a charge signal.
  • the charge signal may be sent after a predetermined time from when the burst signal turns on, and then a laser oscillation synchronization signal TR may be sent as an external trigger.
  • a laser oscillation synchronization signal TR may be sent as an external trigger.
  • charging of the charge capacitor is carried out after the charge signal has been received.
  • the arrangement was such that burst-on and burst-off are represented by a single burst signal BS, but the arrangement may be such that separate signal lines are used as the burst-on signal and burst-off signal.
  • this invention may be arranged so as to be applied in a processing device other than an exposure device provided that it is one which carries out work based on a laser.
  • the arrangement may be such that, when the oscillation-stopping time Tpp is extremely long (for example one hour or longer), an adjustment oscillation (laser oscillation carried out with the laser suitably screened so that the laser output does not fall incident upon the exposure device 20) is carried out during this oscillation-stopping time, the predetermined target pulse energy Pd is compared with the various pulse energy monitor results of the abovementioned adjustment oscillation during a later continuous pulse oscillation, and the optimum charge voltage values stored in the voltage data table are corrected in accordance with the results of this comparison.
  • an adjustment oscillation laser oscillation carried out with the laser suitably screened so that the laser output does not fall incident upon the exposure device 20
  • the predetermined target pulse energy Pd is compared with the various pulse energy monitor results of the abovementioned adjustment oscillation during a later continuous pulse oscillation, and the optimum charge voltage values stored in the voltage data table are corrected in accordance with the results of this comparison.
  • this invention can be applied to exposure devices of both the stepper type and scan type.
  • the laser device is arranged so as to perform control relating to the burst operation using the burst-on signal and burst-off signal sent from the working device side, and, therefore, if laser oscillation synchronization signal acting as a trigger signal for a continuous pulse oscillation is transmitted after the burst-on signal, and a burst-off signal is transmitted after the laser oscillation synchronization signal, it is possible to carry out a computation for the excitation strength from the instant when the burst-on signal is input until the instant when the first laser oscillation synchronization signal is input, and thus there are the following advantages.
  • the arrangement in this invention is such that the target energy value for the continuous pulse oscillation set in advance is corrected using the results of comparisons between the laser monitor output on the processing device side and the laser monitor output on the laser device side, and laser output constancy control is performed using the corrected target energy value as the target value, it follows that variations in the transmittance of the laser output and variations in the laser output monitor are canceled, and accurate and highly precise laser output constancy control can be achieved.

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Electromagnetism (AREA)
  • Plasma & Fusion (AREA)
  • Mechanical Engineering (AREA)
  • Lasers (AREA)
  • Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
  • Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)
  • Laser Beam Processing (AREA)
EP96928726A 1995-08-31 1996-09-02 Bearbeitungsmaschine mit laserstrahl sowie laser Withdrawn EP0873812A4 (de)

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JP223908/95 1995-08-31
JP22390895 1995-08-31
JP95531/96 1996-04-17
JP8095531A JP2724993B2 (ja) 1995-08-31 1996-04-17 レーザ加工装置およびレーザ装置
PCT/JP1996/002467 WO1997007926A1 (fr) 1995-08-31 1996-09-02 Machine d'usinage par faisceau laser, et laser

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EP0873812A1 true EP0873812A1 (de) 1998-10-28
EP0873812A4 EP0873812A4 (de) 2000-04-26

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EP (1) EP0873812A4 (de)
JP (1) JP2724993B2 (de)
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WO (1) WO1997007926A1 (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10244105B3 (de) * 2002-02-26 2004-09-16 Xtreme Technologies Gmbh Verfahren zur Energiestabilisierung gasentladungsgepumpter, in definierten Impulsfolgen betriebener Strahlungsquellen
WO2004112205A1 (en) * 2003-06-19 2004-12-23 Multiwave Photonics, Sa Laser source with configurable output beam characteristics
US6914920B2 (en) 2002-02-26 2005-07-05 Xtreme Technologies Gmbh Method for energy stabilization of gas discharged pumped in selected impulse following driven beam sources

Families Citing this family (36)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3830591B2 (ja) * 1996-11-05 2006-10-04 株式会社小松製作所 レーザ装置
US6516013B1 (en) 1999-12-20 2003-02-04 Lambda Physik Ag Laser beam monitoring apparatus and method
US6490307B1 (en) 1999-03-17 2002-12-03 Lambda Physik Ag Method and procedure to automatically stabilize excimer laser output parameters
US6965624B2 (en) * 1999-03-17 2005-11-15 Lambda Physik Ag Laser gas replenishment method
US6389052B2 (en) 1999-03-17 2002-05-14 Lambda Physik Ag Laser gas replenishment method
US6727731B1 (en) 1999-03-12 2004-04-27 Lambda Physik Ag Energy control for an excimer or molecular fluorine laser
US6907058B2 (en) 2000-01-25 2005-06-14 Lambda Physik Ag Energy monitor for molecular fluorine laser
US6392743B1 (en) * 2000-02-29 2002-05-21 Cymer, Inc. Control technique for microlithography lasers
US6618403B2 (en) 2000-03-16 2003-09-09 Lambda Physik Ag Method and apparatus for compensation of beam property drifts detected by measurement systems outside of an excimer laser
US6834066B2 (en) 2000-04-18 2004-12-21 Lambda Physik Ag Stabilization technique for high repetition rate gas discharge lasers
US6862307B2 (en) * 2000-05-15 2005-03-01 Lambda Physik Ag Electrical excitation circuit for a pulsed gas laser
US6747741B1 (en) 2000-10-12 2004-06-08 Lambda Physik Ag Multiple-pass interferometric device
US6955956B2 (en) * 2000-12-26 2005-10-18 Semiconductor Energy Laboratory Co., Ltd. Method of manufacturing a semiconductor device
US6998620B2 (en) * 2001-08-13 2006-02-14 Lambda Physik Ag Stable energy detector for extreme ultraviolet radiation detection
JP4647372B2 (ja) * 2005-04-11 2011-03-09 住友重機械工業株式会社 レーザ加工装置
TWI330563B (en) 2007-11-28 2010-09-21 Ind Tech Res Inst Programmable laser device and method for controlling the same
JP5219623B2 (ja) * 2008-05-23 2013-06-26 三菱電機株式会社 レーザ加工制御装置およびレーザ加工装置
WO2014030645A1 (ja) 2012-08-23 2014-02-27 ギガフォトン株式会社 光源装置及びデータ処理方法
TWI523357B (zh) * 2013-03-19 2016-02-21 Sumitomo Heavy Industries Laser processing device and laser processing method
JP5995767B2 (ja) * 2013-03-28 2016-09-21 住友重機械工業株式会社 レーザ加工装置及びレーザ加工方法
WO2014208111A1 (ja) 2013-06-27 2014-12-31 ギガフォトン株式会社 光ビーム計測装置、レーザ装置及び光ビーム分離装置
EP2822113A3 (de) * 2013-06-28 2015-03-25 Canon Kabushiki Kaisha Pulslaser und fotoakoustische Vorrichtung
US9102011B2 (en) 2013-08-02 2015-08-11 Rofin-Sinar Technologies Inc. Method and apparatus for non-ablative, photoacoustic compression machining in transparent materials using filamentation by burst ultrafast laser pulses
US20150034613A1 (en) 2013-08-02 2015-02-05 Rofin-Sinar Technologies Inc. System for performing laser filamentation within transparent materials
US10017410B2 (en) 2013-10-25 2018-07-10 Rofin-Sinar Technologies Llc Method of fabricating a glass magnetic hard drive disk platter using filamentation by burst ultrafast laser pulses
US10252507B2 (en) 2013-11-19 2019-04-09 Rofin-Sinar Technologies Llc Method and apparatus for forward deposition of material onto a substrate using burst ultrafast laser pulse energy
US11053156B2 (en) 2013-11-19 2021-07-06 Rofin-Sinar Technologies Llc Method of closed form release for brittle materials using burst ultrafast laser pulses
US10005152B2 (en) 2013-11-19 2018-06-26 Rofin-Sinar Technologies Llc Method and apparatus for spiral cutting a glass tube using filamentation by burst ultrafast laser pulses
US9517929B2 (en) 2013-11-19 2016-12-13 Rofin-Sinar Technologies Inc. Method of fabricating electromechanical microchips with a burst ultrafast laser pulses
US10144088B2 (en) 2013-12-03 2018-12-04 Rofin-Sinar Technologies Llc Method and apparatus for laser processing of silicon by filamentation of burst ultrafast laser pulses
US9938187B2 (en) 2014-02-28 2018-04-10 Rofin-Sinar Technologies Llc Method and apparatus for material processing using multiple filamentation of burst ultrafast laser pulses
US9757815B2 (en) 2014-07-21 2017-09-12 Rofin-Sinar Technologies Inc. Method and apparatus for performing laser curved filamentation within transparent materials
WO2016114934A1 (en) 2015-01-13 2016-07-21 Rofin-Sinar Technologies Inc. Method and system for scribing brittle material followed by chemical etching
CN104617479B (zh) * 2015-02-13 2017-12-08 中国工程物理研究院激光聚变研究中心 一种基于前缀脉冲的激光能量稳定装置及其能量稳定方法
WO2017158849A1 (ja) 2016-03-18 2017-09-21 ギガフォトン株式会社 レーザ装置、レーザ装置の制御方法
TWI678342B (zh) 2018-11-09 2019-12-01 財團法人工業技術研究院 形成導角的切割方法

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6355992A (ja) * 1986-08-26 1988-03-10 Mitsubishi Electric Corp レ−ザ加工装置
JPH01210183A (ja) * 1988-02-16 1989-08-23 Mitsubishi Electric Corp レーザ加工装置の出力スタート回路
JP2721887B2 (ja) * 1988-05-06 1998-03-04 東芝電子エンジニアリング株式会社 レーザ加工装置
US5260961A (en) * 1990-11-01 1993-11-09 Florod Corporation Sealed excimer laser with longitudinal discharge and transverse preionization for low-average-power uses
JPH0866781A (ja) * 1994-08-30 1996-03-12 Mitsubishi Electric Corp エキシマレーザビーム照射装置

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
No further relevant documents disclosed *
See also references of WO9707926A1 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10244105B3 (de) * 2002-02-26 2004-09-16 Xtreme Technologies Gmbh Verfahren zur Energiestabilisierung gasentladungsgepumpter, in definierten Impulsfolgen betriebener Strahlungsquellen
US6914920B2 (en) 2002-02-26 2005-07-05 Xtreme Technologies Gmbh Method for energy stabilization of gas discharged pumped in selected impulse following driven beam sources
WO2004112205A1 (en) * 2003-06-19 2004-12-23 Multiwave Photonics, Sa Laser source with configurable output beam characteristics

Also Published As

Publication number Publication date
WO1997007926A1 (fr) 1997-03-06
KR19990044284A (ko) 1999-06-25
JPH09122949A (ja) 1997-05-13
TW345517B (en) 1998-11-21
US6084897A (en) 2000-07-04
EP0873812A4 (de) 2000-04-26
JP2724993B2 (ja) 1998-03-09

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